Zugzwang
Zugzwang is a position where any move you play makes your situation worse, but you still have to move.
Chess has no pass. If every legal move loses a pawn, a key square, or the opposition, you are in zugzwang. Endgames produce it because there are so few pieces that each king step changes the evaluation.
This is a trebuchet: whoever must move loses their pawn. White to move cannot hold e4, and Black’s king then takes the opposition and escorts the remaining pawn.
If it were Black’s turn, White would win instead. That is why triangulation and opposition exist — they are tools for handing the move to the opponent.